1. Field of the Invention
This invention pertains to microphones and more particularly to ear microphones of the vibration pickup type that receive sound through bone conduction.
2. Description of the Prior Art
The high noise level existing in many environments such as on factory floors, and in the cockpits of small aircraft or in motorcycles, for example, prevents use of conventional microphones for electronic communication by, for example, intercom or radio, since conventional microphones pick up the noise making speech difficult to understand. Further, a person working in such environment often does not have the free use of his hands. In the factory, the person may be working with his hands, and while flying an airplane or operating a motor vehicle he will obviously need his hands to control the plane or motor vehicle. Therefore, microphones which need not be hand held and which are not sensitive to environmental noise are desirable in these and similar environments.
Ear microphones of the vibration pickup type are known which are fitted into the external auditory canal of the ear of the user to pickup his voice which is conducted through his bones to the external auditory canal wall. Such an ear microphone has been described and disclosed in U.S. Pat. No. 4,150,262.
Such devices however, pick up a substantial amount of environmental acoustical energy. Further, contamination from moisture or other pollutants can damage the microphone. Additionally, such devices can become extremely uncomfortable in the user's ear after extended use.
It is thus an object of the present invention to provide a microphone of the type designed to be inserted into the ear canal of the user to provide an electrical signal derived from the user's voice or other vibrations.
It is still another object of the invention to provide an ear microphone which effectively dampens environmental acoustic energy to cancel environmental noise.
It is yet another object of the invention to provide an ear microphone which is comfortable for extended periods of use in the user's ear.
It is a further object of this invention to provide an ear microphone that is impervious to moisture and environmental contaminants.